Buggy code:
final class ConcreteResourceRegistration extends AbstractResourceRegistration { @ SuppressWarnings ( "unused" ) private volatile Map < String , NodeSubregistry > children ; @ SuppressWarnings ( "unused" ) private volatile Map < String , OperationEntry > operations ; @ SuppressWarnings ( "unused" ) private volatile DescriptionProvider descriptionProvider ; @ SuppressWarnings ( "unused" ) private volatile Map < String , AttributeAccess > attributes ; private final boolean runtimeOnly ; private static final AtomicMapFieldUpdater < ConcreteResourceRegistration , String , NodeSubregistry > childrenUpdater = AtomicMapFieldUpdater . newMapUpdater ( AtomicReferenceFieldUpdater . newUpdater ( ConcreteResourceRegistration . class , Map . class , "children" ) ) ; private static final AtomicMapFieldUpdater < ConcreteResourceRegistration , String , OperationEntry > operationsUpdater = AtomicMapFieldUpdater . newMapUpdater ( AtomicReferenceFieldUpdater . newUpdater ( ConcreteResourceRegistration . class , Map . class , "operations" ) ) ; private static final AtomicMapFieldUpdater < ConcreteResourceRegistration , String , AttributeAccess > attributesUpdater = AtomicMapFieldUpdater . newMapUpdater ( AtomicReferenceFieldUpdater . newUpdater ( ConcreteResourceRegistration . class , Map . class , "attributes" ) ) ; private static final AtomicReferenceFieldUpdater < ConcreteResourceRegistration , DescriptionProvider > descriptionProviderUpdater = AtomicReferenceFieldUpdater . newUpdater ( ConcreteResourceRegistration . class , DescriptionProvider . class , "descriptionProvider" ) ; ConcreteResourceRegistration ( final String valueString , final NodeSubregistry parent , final DescriptionProvider provider , final boolean runtimeOnly ) { } @ Override public boolean isRuntimeOnly ( ) { } @ Override public boolean isRemote ( ) { } @ Override public ManagementResourceRegistration registerSubModel ( final PathElement address , final DescriptionProvider descriptionProvider ) { } @ Override public void registerSubModel ( final PathElement address , final ManagementResourceRegistration subModel ) { } @ Override OperationStepHandler getOperationHandler ( final ListIterator < PathElement > iterator , final String operationName , OperationStepHandler inherited ) { } @ Override OperationStepHandler getInheritableOperationHandler ( final String operationName ) { } @ Override void getOperationDescriptions ( final ListIterator < PathElement > iterator , final Map < String , OperationEntry > providers , final boolean inherited ) { } @ Override void getInheritedOperationEntries ( final Map < String , OperationEntry > providers ) { } @ Override public void registerOperationHandler ( final String operationName , final OperationStepHandler handler , final DescriptionProvider descriptionProvider , final boolean inherited , EntryType entryType ) { } @ Override public void registerOperationHandler ( final String operationName , final OperationStepHandler handler , final DescriptionProvider descriptionProvider , final boolean inherited , EntryType entryType , EnumSet < OperationEntry . Flag > flags ) { } @ Override public void registerReadWriteAttribute ( final String attributeName , final OperationStepHandler readHandler , final OperationStepHandler writeHandler , AttributeAccess . Storage storage ) { } @ Override public void registerReadOnlyAttribute ( final String attributeName , final OperationStepHandler readHandler , AttributeAccess . Storage storage ) { } @ Override public void registerMetric ( String attributeName , OperationStepHandler metricHandler ) { } @ Override public void registerProxyController ( final PathElement address , final ProxyController controller ) throws IllegalArgumentException { } @ Override public void unregisterProxyController ( final PathElement address ) throws IllegalArgumentException { } NodeSubregistry getOrCreateSubregistry ( final String key ) { } @ Override DescriptionProvider getOperationDescription ( final Iterator < PathElement > iterator , final String operationName , DescriptionProvider inherited ) { if ( iterator . hasNext ( ) ) { DescriptionProvider ourInherited = getInheritableOperationDescription ( operationName ) ; DescriptionProvider inheritance = ( ourInherited == null ) ? inherited : ourInherited ; final PathElement next = iterator . next ( ) ; final NodeSubregistry subregistry = children . get ( next . getKey ( ) ) ; if ( subregistry == null ) { return null ; } return subregistry . getOperationDescription ( iterator , next . getValue ( ) , operationName , inheritance ) ; } else { final OperationEntry entry = ConcreteResourceRegistration . operationsUpdater . get ( this , operationName ) ; <START_BUG> return entry == null ? null : entry . getDescriptionProvider ( ) ; <END_BUG> } } @ Override DescriptionProvider getInheritableOperationDescription ( final String operationName ) { } @ Override Set < OperationEntry . Flag > getOperationFlags ( ListIterator < PathElement > iterator , String operationName , Set < OperationEntry . Flag > inherited ) { } @ Override Set < OperationEntry . Flag > getInheritableOperationFlags ( String operationName ) { } @ Override DescriptionProvider getModelDescription ( final Iterator < PathElement > iterator ) { } @ Override Set < String > getAttributeNames ( final Iterator < PathElement > iterator ) { } @ Override AttributeAccess getAttributeAccess ( final ListIterator < PathElement > iterator , final String attributeName ) { } @ Override Set < String > getChildNames ( final Iterator < PathElement > iterator ) { } @ Override Set < PathElement > getChildAddresses ( final Iterator < PathElement > iterator ) { } @ Override ProxyController getProxyController ( Iterator < PathElement > iterator ) { } @ Override void getProxyControllers ( Iterator < PathElement > iterator , Set < ProxyController > controllers ) { } ManagementResourceRegistration getResourceRegistration ( Iterator < PathElement > iterator ) { } }

Fix:
return entry == null ? inherited : entry . getDescriptionProvider ( ) ;